The video shows West's vehicle being pulled over by two unmarked police vehicles that have their blue lights flashing.

Moynihan approaches West's vehicle, opens the driver's door and West lunges out of the vehicle, shooting the officer at close range, the video shows.

While the video does not clearly show it, as West runs away he continues to fire at other officers, Boston Police Commissioner Williams Evans said.

Community leaders were present during the news conference as the video was released.

"There are a small, but relevant, group of people who represent a danger to the community, and we need to be very aware that the work of the police officers is very important," said Mark V. Scott, associate pastor at Azusa Christian Community in Dorchester. "I think people understand that the decisions Mr. West made put his life in grave jeopardy."

The Rev. Jeffrey Brown, of the 12th Baptist church, urged residents to "stay cam during this crisis."

"I have to commend the police commissioner and the district attorney for the swiftness in which we were able to see this video."

"The public has a justifiable interest in knowing and understanding how the police force performs duties on their behalf," Suffolk County District Attorney Dan Conley said. "Put goal going forward is that we are one people, in one city."

Conley said the investigation remains "open and active."

Moynihan is "remarkably doing well," said Evans, who added that the officer may soon be released from the rehabilitation facility where he is recovering.

"There are no winners here. We have an officer who was seriously injured, and we have a family who is grieving the loss of a loved one," Evans said.

West had a long criminal history with juvenile appearances and more than 20 adult appearances, including several gun cases.

Moynihan is a former Army Ranger who served in Iraq in 2006-2007 and was honored at the White House in May with the National Association of Police Organizations TOP COPS award.

Moynihan received the award for being one of the first responders in Watertown following the April 2013 gun battle with the Boston Marathon bombers.

Moynihan had helped transit police Officer Dic Donohue, who was shot in the leg and nearly bled to death when police tried to apprehend Tamerlan and Dzhokhar Tsarnaev, Lt. Michael McCarthy said.